|
|
||||||||
/HCO3
exchange activity in
tracheal epithelial cells
Departments of 1 Medicine and 2 Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati School of Medicine, Cincinnati, Ohio 45267; and 3 Department of Medicine, University of North Carolina, Chapel Hill North Carolina 27599
Thickening of airway mucus and lung
dysfunction in cystic fibrosis (CF) results, at least in part, from
abnormal secretion of Cl
and HCO3
across the tracheal epithelium. The mechanism of the defect in HCO3
secretion is ill defined; however, a lack of
apical Cl
/HCO3
exchange may exist in
CF. To test this hypothesis, we examined the expression of
Cl
/HCO3
exchangers in tracheal
epithelial cells exhibiting physiological features prototypical of
cystic fibrosis [CFT-1 cells, lacking a functional cystic fibrosis
transmembrane conductance regulator (CFTR)] or normal trachea (CFT-1
cells transfected with functional wild-type CFTR, termed CFT-WT). Cells
were grown on coverslips and were loaded with the pH-sensitive dye
2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, and
intracellular pH was monitored. Cl
/HCO3
exchange activity increased by ~300% in cells transfected with functional CFTR, with activities increasing from 0.034 pH/min in CFT-1
cells to 0.11 in CFT-WT cells (P < 0.001, n = 8). This activity was significantly inhibited by
DIDS. The mRNA expression of the ubiquitous basolateral AE-2
Cl
/HCO3
exchanger remained unchanged.
However, mRNA encoding DRA, recently shown to be a
Cl
/HCO3
exchanger (Melvin JE, Park K,
Richardson L, Schultheis PJ, and Shull GE. J Biol Chem 274:
22855-22861, 1999.) was abundantly expressed in cells expressing
functional CFTR but not in cells that lacked CFTR or that expressed
mutant CFTR. In conclusion, CFTR induces the mRNA expression of
"downregulated in adenoma" (DRA) and, as a result, upregulates the
apical Cl
/HCO3
exchanger activity in
tracheal cells. We propose that the tracheal HCO3
secretion defect in patients with CF is partly due to the
downregulation of the apical Cl
/HCO3
exchange activity mediated by DRA.
cystic fibrosis transmembrane conductance regulator; cystic fibrosis; trachea; bicarbonate secretion; downregulated in adenoma; chloride ion/bicarbonate exchange
This article has been cited by other articles:
![]() |
J. L. Kreindler, C. A. Bertrand, R. J. Lee, T. Karasic, S. Aujla, J. M. Pilewski, R. A. Frizzell, and J. K. Kolls Interleukin-17A induces bicarbonate secretion in normal human bronchial epithelial cells Am J Physiol Lung Cell Mol Physiol, February 1, 2009; 296(2): L257 - L266. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. T. Nickell, N. K. Kleene, and S. J. Kleene Mechanisms of neuronal chloride accumulation in intact mouse olfactory epithelium J. Physiol., September 15, 2007; 583(3): 1005 - 1020. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Lamprecht and U. Seidler The emerging role of PDZ adapter proteins for regulation of intestinal ion transport Am J Physiol Gastrointest Liver Physiol, November 1, 2006; 291(5): G766 - G777. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Xu, J. Henriksnas, S. Barone, D. Witte, G. E. Shull, J. G. Forte, L. Holm, and M. Soleimani SLC26A9 is expressed in gastric surface epithelial cells, mediates Cl-/HCO3- exchange, and is inhibited by NH4+ (Report) Am J Physiol Cell Physiol, August 1, 2005; 289(2): C493 - C505. [Abstract] [Full Text] [PDF] |
||||
![]() |
O. Furukawa, L. C. Bi, P. H. Guth, E. Engel, M. Hirokawa, and J. D. Kaunitz NHE3 inhibition activates duodenal bicarbonate secretion in the rat Am J Physiol Gastrointest Liver Physiol, January 1, 2004; 286(1): G102 - G109. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Petrovic, X. Ju, S. Barone, U. Seidler, S. L. Alper, H. Lohi, J. Kere, and M. Soleimani Identification of a basolateral Cl-/HCO3- exchanger specific to gastric parietal cells Am J Physiol Gastrointest Liver Physiol, June 1, 2003; 284(6): G1093 - G1103. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. N Chernova, L. Jiang, B. E Shmukler, C. W Schweinfest, P. Blanco, S. D Freedman, A. K Stewart, and S. L Alper Acute regulation of the SLC26A3 congenital chloride diarrhoea anion exchanger (DRA) expressed in Xenopus oocytes J. Physiol., May 15, 2003; 549(1): 3 - 19. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. M Paradiso, R. D Coakley, and R. C Boucher Polarized distribution of HCO3- transport in human normal and cystic fibrosis nasal epithelia J. Physiol., April 1, 2003; 548(1): 203 - 218. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. J. Hug, T. Tamada, and R. J. Bridges CFTR and Bicarbonate Secretion to Epithelial Cells Physiology, February 1, 2003; 18(1): 38 - 42. [Abstract] [Full Text] [PDF] |
||||
![]() |
S Tate, G MacGregor, M Davis, J A Innes, and A P Greening Airways in cystic fibrosis are acidified: detection by exhaled breath condensate Thorax, November 1, 2002; 57(11): 926 - 929. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Sterling, N. J. D. Brown, C. T. Supuran, and J. R. Casey The functional and physical relationship between the DRA bicarbonate transporter and carbonic anhydrase II Am J Physiol Cell Physiol, November 1, 2002; 283(5): C1522 - C1529. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Lohi, S. Makela, K. Pulkkinen, P. Hoglund, M.-L. Karjalainen-Lindsberg, P. Puolakkainen, and J. Kere Upregulation of CFTR expression but not SLC26A3 and SLC9A3 in ulcerative colitis Am J Physiol Gastrointest Liver Physiol, September 1, 2002; 283(3): G567 - G575. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Bagorda, L. Guerra, F. Di Sole, C. Hemle-Kolb, R. A. Cardone, T. Fanelli, S. J. Reshkin, S. M. Gisler, H. Murer, and V. Casavola Reciprocal Protein Kinase A Regulatory Interactions between Cystic Fibrosis Transmembrane Conductance Regulator and Na+/H+ Exchanger Isoform 3 in a Renal Polarized Epithelial Cell Model J. Biol. Chem., June 7, 2002; 277(24): 21480 - 21488. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Kunzelmann and M. Mall Electrolyte Transport in the Mammalian Colon: Mechanisms and Implications for Disease Physiol Rev, January 1, 2002; 82(1): 245 - 289. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Greeley, H. Shumaker, Z. Wang, C. W. Schweinfest, and M. Soleimani Downregulated in adenoma and putative anion transporter are regulated by CFTR in cultured pancreatic duct cells Am J Physiol Gastrointest Liver Physiol, November 1, 2001; 281(5): G1301 - G1308. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. J. Gillie, A. J. Pace, R. J. Coakley, B. H. Koller, and P. M. Barker Liquid and Ion Transport by Fetal Airway and Lung Epithelia of Mice Deficient in Sodium-Potassium-2-Chloride Transporter Am. J. Respir. Cell Mol. Biol., July 1, 2001; 25(1): 14 - 20. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. Ahn, K. H. Kim, J. A. Lee, J. Y. Kim, J. Y. Choi, O. W. Moe, S. L. Milgram, S. Muallem, and M. G. Lee Regulatory Interaction between the Cystic Fibrosis Transmembrane Conductance Regulator and HCO3- Salvage Mechanisms in Model Systems and the Mouse Pancreatic Duct J. Biol. Chem., May 11, 2001; 276(20): 17236 - 17243. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z. Wang, S. Petrovic, E. Mann, and M. Soleimani Identification of an apical Cl-/HCO3- exchanger in the small intestine Am J Physiol Gastrointest Liver Physiol, March 1, 2002; 282(3): G573 - G579. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Lipecka, M. Bali, A. Thomas, P. Fanen, A. Edelman, and J. Fritsch Distribution of ClC-2 chloride channel in rat and human epithelial tissues Am J Physiol Cell Physiol, April 1, 2002; 282(4): C805 - C816. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |